It certainly should not be legal...

  If you do not have a backup available to restore to, we regret that we have no
  alternate method for preventing the ads from being displayed. However, we will
  be happy to make it up to you with in-game currency for Bejeweled Blitz,
  Plants vs. Zombies 2, Solitaire Blitz, or Zuma Blitz. Please contact support
  and provide the receipt from your original purchase of Bejeweled or Bejeweled
  HD.

https://help.ea.com/en-us/help/bejeweled/bejeweled-classic/s...